If Andy Murray wants to win at Wimbledon he should stop eating bananas on Centre Court and refrain from helping himself to ice cold drinks during breaks.

So says Oxford biological sciences graduate George Cooper, who says the current fad for eating fruit and raw vegetables upsets the digestion and is particularly inappropriate for athletes seeking quick energy.

“Human beings are not designed to digest raw food, and we never have been,” Cooper writes in Be Your Own Nutritionist, Rethink Your Relationship with Food.

“In the case of fruit and veg, much of it can pass through us undigested.”

Cooper is alarmed by what he has seen of Murray’s diet. “Bananas are rich in fibre and starch but they are not going to be any use during a tennis match,” says Cooper.

“They also contain potassium but this would be better taken in a lukewarm drink. The banana just sits there as a lump in the stomach and does no good to the tennis player.”

As for cold drinks, they divert warm blood from the muscles and skin to heat up the stomach again. “It would be better for Murray to pour cold water over his head, but it’s rarely that hot in Wimbledon.”